In pharmacology, PRN is an abbreviation meaning what?

• A. As needed
• B. Immediately
• C. Every four hours
• D. Before meals

Answer: (A)

PRN means “as needed.” In pharmacology, this label is used for meds that aren’t given on a fixed schedule but are taken only when symptoms require them. It’s common for rescue or symptom-relief drugs, where the patient can use the medication at the discretion of a clinician’s instructions, often up to a safe maximum. That’s why the best answer is “as needed.” The other phrases describe fixed timing or conditions (immediate dosing, regular intervals like every four hours, or timing relative to meals), which aren’t compatible with a PRN approach.